Product Description:

B&R Automation produces the 7EX477.50-2 communication controller within the System 2003 Controllers series. This module functions as a fieldbus master that coordinates distributed I/O stations on RS485 networks in industrial automation cells. By providing protocol handling, node addressing, and electrical isolation in a single housing, it simplifies the integration of remote sensors and actuators with the main PLC. This arrangement allows the controller to exchange process data with remote modules while keeping bus management centralized inside one unit.

Communication takes place through a 9-pin D-sub socket (F) that connects directly to the bus without intermediate coupling hardware. Data are exchanged over a shielded twisted pair cable segment that can extend up to 1200 m while maintaining a maximum throughput of 2000 kbit/s. The single RS485 port uses external termination resistors and supports a bus topology, so additional repeaters are unnecessary in typical cabinet layouts. Each station address is set locally with a numbered rotary switch, which allows the network layout to be adjusted without changing the controller itself. The interface operates from a 24 VDC supply and remains galvanically separated from the logic section to help prevent ground-loop interference.

In a completed segment, the unit can supervise up to 31 subordinate devices using master/slave remote I/O access. When fitted in a rack, it delivers 14 W of output power for connected System 2003 I/O modules, while its own consumption does not exceed 20 W. Status conditions are reported by the front-mounted diagnostic LEDs, so operating states can be checked quickly during normal use. On-board interface isolation helps keep field-wiring transients away from the controller electronics. Direct bus coupling and the option for external termination allow the line ends to be matched correctly without altering the module hardware.